In about 3200 BC the two earliest civilizations develop in the region where the southwest Asia joins Northwest Africa. Great rivers are a crucial part of the story. the Sumerians settle in what is now southern Iraq, between the mouths of the Euphrates and the Tigris
The most straightforward theory for Western Rome's collapse pins the fall on a string of military losses sustained against outside forces. Rome had tangled with Germanic tribes for centuries, but by the 300s “barbarian” groups like the Goths had encroached beyond the Empire's borders.
D Both A and B should be the answer
